install more optional libs for Travis CI

We have optional dependencies on libseccomp and libcap, but we're not building with them in Travis CI. We should add them.

changed milestone to %Tor: 0.3.5.x-final in legacy/trac

added component::core tor/tor in Legacy / Trac fast-fix in Legacy / Trac milestone::Tor: 0.3.5.x-final in Legacy / Trac owner::catalyst in Legacy / Trac priority::medium in Legacy / Trac resolution::implemented in Legacy / Trac severity::normal in Legacy / Trac sponsor::3-can in Legacy / Trac status::closed in Legacy / Trac tor-ci in Legacy / Trac type::enhancement in Legacy / Trac labels

Patch at https://github.com/torproject/tor/pull/192

Trac:
Sponsor: N/A to Sponsor3-can
Status: assigned to merge_ready

Trac:
Status: merge_ready to needs_review

Trac:
Status: needs_review to merge_ready

Merged to master!

Trac:
Resolution: N/A to implemented
Status: merge_ready to closed

closed

moved from legacy/trac#26560 (moved)

added Feature label and removed 1 deleted label

added CI label and removed 1 deleted label